Polishing compound.



UNITED STATES PA EN onFIo PETER rmmrm, or WASHINGTON, nIsTmcT orconumsm, assreivon To mas mi'rrc PIGMEN'I company, on NEW- YORK, 11.2.,A CORPORATION on NEW xonmromsnmecomronnn.

Specification of Letters Patent.

' No Drawing. Application filed January 15, 1909, Serial No. 472,539.Renewed Karen 30, 1912. Serial PatentedMay 7, 1912.

I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which itappertains to make and use the same.

My invention relates to certain new'and useful improvements in polishingand particularly to the polishing of plate glass by means of the usualpolishing machines employed for that purpose, wherein the plate glass tobepolished is secured upon a sup porting bed or table and is traversedby the customary felt clad polishing blocks which are usually giveneither a circular motion or a reciprocating motion in a rectilinearpath.

My invention resides in the discovery that chemically precipitatedmagnetic oxid of iron, which alone, or mixed only with water, is notadapted. for the polishing of plate glass sin-faces in machines sf thischarac--.

ter, for the reason that it scratches the glass under those conditions,is rendered highly cifectiveas a plate glass polishing agent anddevelops a brilliant luster peculiar to its a use, and with theemployment of a comparatively moderate amount of the chemicallyprecipitated magnetic oxid of iron, provided it is admixed with asuitable quantity of a soluble compound (such as su1-, fate of iron") insolution in water. I'have' discovered that the superior luster incidentto the employment of this mixture of chemically precipitated magneticoxid of iron,

-water, and soluble compound, can be obtained without] increasing theduration of the usual polishing operation, and, in some instances, witha diminution of the olishing period, and, 'furthermore, with t e employment of an amount of the chemically precipitated magnetic oxid .ofiron oftentimes as low as one third of the amountby weight of the rouge,or like polishing agents ordinarily employed in plate glass In carryingout myinvention, whensuI- fate of iron is'employed as the solublecompound, combine the ingredients in such manner that the mixture.ofchemically precipitated magnetic oxid of iron, water and sulfate ofiron, when its ingredients are inti-' mately incorporated with eachother by stirring, shall have a specific gravity of from 1 to 3 de reesBauin, and so that the clear liqu1d, a ter settling, shall have aspecific gravity from at degrees to 1.2 degrees Baum, these proportionsbeing suitable in practice for the production of eflicient and quickresults; although it is obvious that they may be somewhat'varied withoutdeparting from the spirit of the invention,

as -the'conditions of use will vary, 6. g., the

character and velocity of the motion of the polishing blocks, theprevailing temperature, and the like. What-is of importance is that acertain correspondence be maintained between the thickness of themixture (represented by the specific gravity of the freshly stirred upingredients) and the concentration. of'the soluble compound (representedby the specific gravity of the so-' lution after the precipitatedmagnetic oxid has settled) the greater the thickness, the

greater the concentration. This ratio-may ,be a different one for thedifi'erent types of.

polishing machines. The hereinbeforeratios were found well adapted forpolishing.machines wit a reciprocating motion" in rectilinear patIngeneral, I recommend that for expeditious work, a thicker mixture beused in the earlier stages of the process, and a thinner one in thelatter stages.

In utilizing the" polishing; agent thus pre-v pared, the operatorapplies" it to the surface i ally taken up, as is usual in polishingoperations. ofthis general character, by the s imy layer over said padsof feltwit-h'the formation of a layer of the polish thereon. As thepolish;

'ing operation (which usually lasts a number of hours, accordin tothecharacter of themachine and the c aracter of the""p1a t glass itself,"orthe work to be performed upon it) progresses, the glass" becomes highlyheated, so that when the polishing agent'is applied, the waterevaporates in large volume. polishing agent begins to cake upon thepolishing surfaces of the pads of felt, and the chemically precipitatedmagnetic oxid of iron, were it not for the presence of the sulfate ofiron, would thereupon become hard, closely compacted, brittle andinelastic and would scratch the plate glass surface and would adheretenaciously in some places to the glass and gum up, thereby causingirregular working. The presence of the sulfate of iron, however,intimately intermingled with the chemically precipitated magnetic oxidof iron prevents these tendencies, while not interfering with thepolishing effect, but permitting it to proceed to the end with thedevelopment of a brilliant luster characteristic of the employment ofthe mixture. The reason for this combined action of the chemicallyprecipitated magnetic oxid of iron, which is amorphous, and of thesulfate of iron, which is crystalline, is somewhat obscure, but it isprobably to be attributed to the circumstance that the homogeneouslyintermingled amorphous and fine crystalline particles form a cakedsurface on the pads which is more elastic and which does not tend tobecome closely compacted and brittle, as would be the case if thesulfate ofiron, or other -soluble compound,.were not present, but,however, this may be, it -1S a further circumstance of great Under theseconditions the ipaaeee economical'importance in connection with mydiscovery that, as hereinbeforc noted,

the high etficiency and the capacity for producing a peculiarlybrilliant luster obtained by the use of my improved polishing agent issecured at an expenditure of a relatively small amount of the chemicallyprecipitated magnetic oxid of iron, in comparison with the amount byweight of rouge, or other like oxids, natural or artificial, usuallyemployed in the plate glass polishing art.

What I claim is:

1. A polishing agent for plate glass polishing machines, consisting ofchemically precipitated magnetic oxid of iron, water, and a solublecompound; substantially as described.

2. A polishing agent for plate glass polishingmachines, consisting ofchemically precipitated magnetic oxid of iron, water, and a solublecompound, the specific gravity of the mixture when its ingredients areintimately intermingled by stirring being approximately one to threedegrees Baum,

and the specific gravity of liquid solution,

after settling, being approximately .4 to 1.2 degrees Baum;substantially as described.

In testimony whereof I afiix my signature, in presence of two witnesses.

PETER FIREMAN.

Witnesses: .c l

H. M. STERLING, CHAS. J. QNEILL.

